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Fahrenheit to Celsius Converter

Convert °F to °C instantly, with a reference table covering weather, fever thresholds and oven temperatures.

Fahrenheit to Celsius Converter

1 °F = -17.22 °C

Multiply degrees Fahrenheit by 0.5556, then add -17.77777777777778, to get degrees Celsius.

The link carries the values you entered, so whoever opens it sees the same result. Nothing is stored on our side — the numbers travel in the link itself.

Degrees Fahrenheit to degrees Celsius reference table

The conversions people look up most often, rounded to 2 decimal places.

Common degrees Fahrenheit to degrees Celsius conversions
Degree Fahrenheit (°F)Degree Celsius (°C)
-40 °F-40 °C
0 °F-17.78 °C
32 °F0 °C
50 °F10 °C
68 °F20 °C
72 °F22.22 °C
90 °F32.22 °C
98.6 °F37 °C
100.4 °F38 °C
212 °F100 °C
350 °F176.67 °C
400 °F204.44 °C
450 °F232.22 °C

The degrees Fahrenheit people look up most

72 °F = 22.22 °C
The American thermostat default, and a few degrees warmer than most European homes are kept.
98.6 °F = 37 °C
Body temperature, and a figure only oddly precise because it was converted from a round Celsius one.
100.4 °F = 38 °C
The fever threshold, defined in Celsius and converted - which is why it reads so oddly in Fahrenheit.
350 °F = 176.67 °C
The most common American oven temperature; European recipes round it to 180.
400 °F = 204.44 °C
Written as 200 in European recipes, and the setting for roasting rather than baking.

How the fahrenheit to celsius calculation works

Two scales with different zero points and different step sizes, so this needs two operations rather than one:

°C = (°F − 32) × 5/9

Order matters. Subtract the 32 first, then multiply. Doing it the other way round gives an answer that is wrong by about 18 degrees — enough to turn a fever into a normal temperature.

Working through the numbers people actually look up:

Weather. 72°F, the American thermostat default, is (72 − 32) × 5/9 = 22.2°C. A 90°F summer day is 32.2°C, and 0°F — cold but not extraordinary in the northern US — is −17.8°C.

Fever. Normal body temperature of 98.6°F is 37.0°C. The clinical fever threshold of 100.4°F is exactly 38.0°C — that oddly specific Fahrenheit number exists because the underlying definition is the round Celsius one.

Cooking. A 350°F oven is 176.7°C, which European recipes give as 180°C. 400°F is 204.4°C (written as 200°C), and 450°F is 232.2°C (230°C). The rounding is always to the nearest 10°C, so converted oven temperatures are approximate by convention rather than by accident.

Two anchors worth keeping:

  • −40 is identical in both scales. The only crossing point, and a quick check that a formula is the right way round.
  • Subtract 30 and halve for a rough figure: 72 → 42 → 21, against a true 22.2. Good for weather, not for medicine or meat.

For a temperature difference rather than a temperature, multiply by 5/9 and skip the 32 entirely.

Frequently asked questions

Why did Fahrenheit pick such odd reference points?

He set zero at the coldest temperature he could reproduce reliably - a brine of ice, water and ammonium chloride - and placed body temperature near 96 so the scale divided neatly in halves. The scale was later redefined against the freezing and boiling points of water, which shifted body temperature to 98.6 and left the original anchors looking arbitrary.

Is an oven dial accurate enough for the converted figure to matter?

Usually not. A domestic oven swings 10 to 15°C either side of the set point as the element cycles, and plenty are miscalibrated by more than that, so the 3.3°C between a converted 350°F and a European 180°C is well inside the noise. An oven thermometer is worth more than a precise conversion. Sugar work and chocolate tempering are the exceptions, and they are measured in the pan.

Where does the subtract-30-and-halve trick break down?

At oven temperatures. Over the ordinary weather range it is fine: 50°F gives 10 against a true 10.0, and 90°F gives 30 against 32.2. Push it to 350°F and it returns 160 against a true 176.7 - nearly 17 degrees adrift, and enough to undercook. The error grows with the number, because halving is not the same as multiplying by five ninths.

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Further reading